Determination of solid products from the de-polymerization of poly(trimethylene terephthalate) in supercritical methanol

Zhang, Changming; Xu, Long; Zhang, Haohong; Yang, Jing; Du, Jianjun; Liu, Zhenyu

doi:10.1016/j.chroma.2004.08.146

Cited by 12 publications

(6 citation statements)

References 6 publications

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“…Since the degradation of polyesters is very difficult, recycling and recovery of the waste polyester materials are necessary. For this purpose, several methods have been proposed, such as hydrolysis, glycolysis, methanolysis, and aminolysis. − The methanolysis of polyesters will produce DMT as an intermediate. − Since an installation for recycling of polyesters via DMT can be located in the polymer production line and the quality of the produced DMT is the same as that of virgin DMT, and also the recovery and recycling of methanol are easy, the methanolysis is therefore regarded as a prosperous method. The recovery and purification of DMT usually involve crystallization processes leading to the selection of an appropriate solvent based on the solubility of DMT being indispensable.…”

Section: Introductionmentioning

confidence: 99%

Solubility and Thermodynamic Modeling of Dimethyl Terephthalate in Pure Solvents and the Evaluation of the Mixing Properties of the Solutions

Zhang

et al. 2019

J. Chem. Eng. Data

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In this work, the solubility of dimethyl terephthalate (DMT) in alcohols (methanol, ethanol, n-propanol, i-propanol, n-butanol, and i-butanol), esters (ethyl acetate, i-propyl acetate, n-propyl acetate, n-butyl acetate, n-amyl acetate, and methyl propionate), ketones (acetone, methyl ethyl ketone, and cyclohexanone), acetonitrile, and chloroform was experimentally determined. The solubility of DMT in these solvents follows the order: chloroform > esters and ketones > acetonitrile > alcohols and increases with increasing temperature. The solubility of DMT as a function of temperature has been regressed in terms of three semiempirical models (modified Apelblat, λh, and three-parameter Van’t Hoff) and two activity coefficient models (Wilson and nonrandom two-liquid), which gave a maximum relative average deviation of 2.32% and a maximum root-mean-square deviation of 31.63 × 10–5. Better fittings were obtained with the activity coefficient models. In addition, the mixing properties (Gibbs energy, enthalpy, entropy, as well as activity coefficients and reduced excess enthalpy at infinitesimal concentration) were evaluated using the Wilson model.

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Section: Introductionmentioning

confidence: 99%

Solubility and Thermodynamic Modeling of Dimethyl Terephthalate in Pure Solvents and the Evaluation of the Mixing Properties of the Solutions

Zhang

et al. 2019

J. Chem. Eng. Data

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“…Many chemical recycling methods have already been developed [4]. Among such methods, supercritical fluid (SCF) technologies are considered as potentially attractive due to the environmental friendly nature of SCF [7,8]. In its critical point (or beyond that) a compound becomes a SCF and possesses: (i) low viscosity and higher diffusivities as compared to the liquid state; and (ii) high kinetic energy as compared to the gas state.…”

Section: Introductionmentioning

confidence: 99%

“…In its critical point (or beyond that) a compound becomes a SCF and possesses: (i) low viscosity and higher diffusivities as compared to the liquid state; and (ii) high kinetic energy as compared to the gas state. Therefore, reactions under SCF are expected to be faster as compared to normal liquid-gas conditions [8]. Processes based on SCF have been focused on depolymerization.…”

Section: Introductionmentioning

confidence: 99%

Poisoning Effects of Water and Dyes on the [Bmim][BF4] Catalysis of Poly(Ethylene Terephthalate) (PET) Depolymerization under Supercritical Ethanol

et al. 2017

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Supercritical ethanolysis (scEtOH) is a method that allows the production of monomers, e.g., diethyl terephthalate (DET), from Polyethylene terephthalate PET chemical recycling. The use of the ionic liquids (ILs) such as 1-n-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) as a catalyst has advantages in such processes by enhancing the yield at reduced times, as shown in previous work from our lab. However, the effects of water and dyes (from the coloured PET-bottles) regarding those advantages have not been investigated. Here, a study of the effects of water and dyes on IL-catalysis is provided. Results showed that the yield related to DET formation was 98% when anhydrous ethanol was employed, but decreased to 30% (or less) when water was present in the reaction even in low amounts. Furthermore, the DET-formation yield also decreased to 66% or to 21% if 2-aminoanthraquinone or zinc phthalocyanine were present, respectively, even in anhydrous conditions. Poisoning effect on the IL-catalysis was observed in both cases. Thus, these data are relevant for expanding the study of ILs as catalysts in this and other reaction systems.

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“…Accordingly, their mass transfer rates approach those in gases, while solvation properties similar to conventional liquid solvents . The depolymerization reactions of common polymers such as polycarbonate (PC) , poly(ethylene terephthalate) (PET) , poly(trimethylene terephthalate) (PTT) , poly(butylene terephthalate) (PBT) , polyimide (PI) and polyethylene (PE) have been studied. However, few studies have focused on depolymerization of PEN , and provided quite limited information.…”

Section: Introductionmentioning

confidence: 99%

Depolymerization of poly(ethylene naphthalate) in fused silica capillary reactor and autoclave reactor from 240 to 280°C in subcritical water

Bei

Wang

et al. 2017

Polymer Engineering & Sci

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Depolymerization of poly(ethylene naphthalate) (PEN) in subcritical water was performed in a fused silica capillary reactor (FSCR) and an autoclave reactor. The phase behaviors of PEN in water during the heating-cooling process in the FSCR were observed under microscope and images were captured by digital camera. Reaction conditions for PEN hydrolysis in the autoclave reactor were chosen based on the experimental results obtained from the FSCR. Under autogenous pressures in the autoclave reactor, the effects of the water/PEN mass ratio (8.0 g/1.0 g to 16.0 g/1.0 g), reaction temperature (240-2808C) and reaction time (5-60 min) on the depolymerization yield and products yields were investigated. The main products of depolymerization were identified and quantified as 2,6naphthalene dicarboxylic acid (2,6-NDA) and ethylene glycol (EG). PEN was completely depolymerized at 2608C in 60 min with an optimal water/PEN mass ratio of 12.0 g/1.0 g (12:1). The yields of 2,6-NDA and EG were optimized to 83.1% and 79.7%, respectively. Reaction kinetics analysis showed that the PEN depolymerization in subcritical water was first-order and the activation energy was 95 kJ mol 21 . Additionally, a reaction pathway was proposed based on the experimental results. POLYM. ENG. SCI.,

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Determination of solid products from the de-polymerization of poly(trimethylene terephthalate) in supercritical methanol

Cited by 12 publications

References 6 publications

Solubility and Thermodynamic Modeling of Dimethyl Terephthalate in Pure Solvents and the Evaluation of the Mixing Properties of the Solutions

Solubility and Thermodynamic Modeling of Dimethyl Terephthalate in Pure Solvents and the Evaluation of the Mixing Properties of the Solutions

Poisoning Effects of Water and Dyes on the [Bmim][BF4] Catalysis of Poly(Ethylene Terephthalate) (PET) Depolymerization under Supercritical Ethanol

Depolymerization of poly(ethylene naphthalate) in fused silica capillary reactor and autoclave reactor from 240 to 280°C in subcritical water

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